Automatic control of the distributor of an internal combustion engine



2,827,889 OR OF March 25, 1958 M. L. SMITLEY AUTOMATIC CONTROL OF THE DISTRIBUT AN INTERNAL COMBUSTION ENGINE Filed March 28, 1955 TTORNE;S

i N 2,827,889 e Patented Mar. 25, 1958 AUTOMATIC CONTROL OF THE DISTRIBUTO OF AN INTERNAL COMBUSTION ENGINE Marion L. Smitley, Huntington Woods, Mich., assignor to Holley Carburetor Company, Detroit, Mich., a corporation of Michigan Application March 28, 1955, Serial No. 497,148

12 Claims. (Cl. 123-117) The present invention relates to automatic control of the distributor Oif an internal combustion engine. It is an object of the present invention to provide. means capable of effecting substantially instantaneous spark adjustment in response to abrupt changes in engine load without affecting normal control jointly responsive to engine speed and load.

It is an object of the present invention to provide an improved pressure responsive distributor capable of effecting substantiallyinstantaneous spark adjustment in response to abrupt changes in engine load without affecting normal control jointly responsive to engine speed and load.

It is a further object of the present invention to provide pressure responsive distributor control comprising time delayed means jointly responsive to speed and load, and substantially instantaneously operating over-riding means responsive primarilyto load.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein the figure is a diagrammatic drawing of the present invention.

In the figure there is diagrammatically shown at a conventional spark distributor including an angularly adjustable plate 12 movable to advance or retard the spark. Suitable spring means (not shown) are provided as is customary, tending to adjust plate 12 in the direction required to retard the spark. A link 14 is connected to plate 12 and is assumed to be so connected thereto that movement of the link 14 in the direction of the arrow, results in retarding the spark.

The link 14 is connected to a flexible diaphragm 16 sealed at its edges in a casing 18 and exposed to atmosphere at the right side as viewed in the figure.

In the casing 18 is another diaphragm 20 sealed at its edges thereto and defining with said first diaphragm and said casing a sealed chamber 22. The end of the casing to the left in the figure is closed, so that diaphragm 20 defines therewith another sealed chamber 24. A compression spring 26, adjustable by a screw seat 28 is provided and urges diaphragm 20 toward diaphragm 16.

The structure so far described is designed to be connected to a conventional carburetor indicated diagrammatically at 3i) and comprising a barrel 32 including a venturi 34 in which is located a fuel nozzle 36, the barrel being connected to the manifold 38 of the engine and having the usual throttle plate 40 between the nozzle and manifold.

As is well understood in the art, manifold vacuum is primarily dependent on engine load and pressure in the throat of the venturi 34 is primarily dependent on engine speed.

C'hamber 22 is connected by passage 42 to a branch passage 44 which communicates through a restriction 46 with the throat of the venturi 34. A second branch passage 48 connects to passage 42 through a restriction 50 and connects through another restriction 52 to the interior of the barrel 32 at a point upstream from a movable edge of throttle plate 40 when the throttle is closed, but in position to be traversed by the edge of the throttle on initial opening movement so as to be downstream from the throttle except when'the throttle is closed.

The restrictions 46, 50 and 52 are carefully metered or calibrated to provide a joint control of pressure Within chamber 22 as required. Also, the provision of the restrictions inherently provides a time delay for passage of air into or out of chamber 22.

The chamber 24 is connected by a substantially unrestricted passage 54 to the barrel 32 below the throttle plate so that chamber 24 is effectively subjected to'instantaneous manifold vacuum. Also, it will be observed that chamber 24 is shaped to have a small volume as compared to chamber 22, and this increases the rapidity of response.

With the foregoing construction in mind it will be observed that upon accelerator tip in, abrupt opening of the throttle plate 44) results in a correspondingly abrupt decrease in manifold vacuum, or increase in manifold pressure. While this decrease manifold vacuum is elfective on restricted port 52, a time interval is required before air can be bled into chamber 22 through restrictions 50 and 52. During this interval, the advanced spark will cause accelerating detonation unless it is quickly retarded.

Chamber 24, having substantially unrestrictedcommunication with the manifold will be affected substantially instantaneously by the drop in manifold vacuum. Air flowing through passage 54 into chamber 24 permits the increased pressure and the spring 26 to push diaphragm 20 to the right thus purging chamber 22 and resulting in movement to the right of diaphragm 16. This retards the spark immediately, and thus eliminates engine knock on rapid throttle opening movement.

"It will be apparent that spark control by diaphragm 16 is'resumed as soon as pressure in chamber 22 comes under the control of passage 42. In other words, control by movement of diaphragm 16 is substantially independent of the position of diaphragm 29. Only when diaphragm 20 is moved abruptly in response to sudden change in load (manifold vacuum) does it enter into control of spark position.

The drawings and the iforegoing specification constitute a description of the improved automatic control of the distributor of an internal combustion engine in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. Automatic distributor adjustment mechanism for an internal combustion engine comprising :a movable spark adjusting member, first means responsive jointly to engine speed and load operatively connected to said member and including time delay means eifective to delay response to changes in speed or load, and second means substantially instantaneously responsive to changes in engine load operatively connected to said member, said first means being operatively associated with said second means to relinquish control to said second means for prompt spark adjustment upon abrupt change in load and resume control thereof after the passage of the time required by said time delay means.

2. Automatic distributor adjustment mechanism for an internal combustion engine comprising a movable spark adjusting member, first means responsive jointly to engine speed and load operatively connected to said member and including time delay means efiective to delay response to changes in speed or load, and second means substantially instantaneously responsive to changes in engine' load 'operatively connected to said member, said first means being operatively associated with said second means to relinquish control to said second means for prompt spark adjustment upon abrupt increase in load and resume control thereof after the passage of the time required by saidtime delay means.

3. Automatic distributor adjustment mechanism for an internal combustion engine having a manifold and a carburetor having a venturi in which a fuel supply nozzle is located, said mechanism comprising a movable spark adjusting member, a casing closed at one end, a first flexible element in said casing defining a first sealed chamber with the first closed end thereof, a second flexible element in said casing defining a second sealed chamber therewith intermediate said elements, means mechanically connecting said secondelernent to said member, restricted passage means connecting said second chamber to said manifold and venturi, and substantially unrestricted passage means connecting said first chamber to said manifold.

4. Mechanism as defined in claim 3 in which said elements are diaphragms.

5. Mechanism as defined in claim 3 comprising spring means in said first chamber urging said first element toward said second element.

- 6. A control device for a movable member adapted to be adjusted in accordance with variations in pressure at 7 two different sources of fluid pressure, comprising a first chamber having a movable wall, a second chamber having two indepedently movable walls one of which is movable in accordance with the movement of the movable wall of said first chamber, resilient means biasing the movable wall of said first chamber in a direction opposite to the direction in which it is urged by dilferential resulting from the prevailing fluid pressure Wlthll'l said first chamber, means connecting the other wall of said second chamber to said member, a substantially unrestricted passage connecting the' interior of said first chamber to a first source of variable pressure, and a restricted passage connecting the interior of said second chamber to a second source of variable pressure.

7. Structure, as defined in claim 6 in which the movable wall of said first chamber and the said one movable wall of said second chamber are constituted by a single member. a

8. Structure as defined in claim 7 in which said movable walls are flexible diaphragms.

9. Structure as defined in claim 7 in which said sources of pressure are sub-atmospheric.

10. Structure as defined inclaim 7 in which the volume of said second chamber is substantially larger than the volume of said first chamber.

11. Automatic distributor adjuster mechanism for an internal combustion engine having a manifold, a carburetor barrel having a venturi in which a fuel supply nozzle is located, and a throttle plate located downstream from said venturi, said mechanism comprising a movable spark adjusting member, a first sealed chamber having a movable wall, a substantially unrestricted passage connecting the interior of said first chamber to the manifold, resilient means connected to said movable wall to oppose movement thereof occasioned by reduction of pressure within said first chamber, a second sealed chamber one wall of which is the movable wall .of said first chamber, said second sealed chamber having a second movable wall adapted to be moved by pressure differential at opposite sides thereof independently of said first movable Wall, re stricted passage means connecting said second chamber to said ventur'i and manifold, and means. connecting said second movable wall to said member.

12. Mechanism as defined in'cla'im 11 in which the capacity of said, first chamber is substantially less than the capacity of said second'chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,365,313 7 Udale Dec. 19, 1944 2,470,366 Ostling May 17, 1949 2,475,717 Ostling July 12, 1949 2,503,645 Westc0tt.et al. Apr. 11, 1950 2,557,527 Colvin et a1 June 19, 1951 2,596,830 Udale May 13, 1952 2,650,581 Short et al. Sept.'1, 1953 

